When Romelu Lukaku scored West Brom’s equaliser in the 5-5 draw against Manchester United in May 2013 it was the 43rd league goal Sir Alex Ferguson’s team had conceded that season.

No one really cared. United were already champions, crowned nearly a month earlier after a straight-forward 3-0 win over Aston Villa at Old Trafford. And anyway, that day at the Hawthorns wasn’t about focusing on what had turned into a defensive calamity. It was about saying goodbye to Fergie.

Ferguson’s successor, David Moyes, didn’t fare any better. The uneventful 1-1 draw with Southampton on the last day of the 2013/14 season – by which time Moyes had already been sacked - saw United concede their 43rd goal that season, too. The difference being that Ferguson’s United had scored 86 goals while Moyes’ team only managed 64.

Sir Alex Ferguson waved goodbye at the Hawthorns.

But two years on, United head to Tottenham on Sunday having conceded just 27 goals league goals all season, a defensive record only bettered by Tottenham themselves. Their clean sheet against Everton at Old Trafford last weekend was their 15th in the league this season – more than anyone else.

It’s been at the other end that Louis van Gaal has had a problem. The 39 goals they’ve scored is only three more than Sunderland and only one more than Bournemouth.

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It’s taken the Dutchman time to get it right. By November in his first season he had already used 13 different combinations at centre-back – a problem exacerbated by his change from a back three to a back four.

This season, Chris Smalling and Daley Blind have started together in all but five of their 31 games in the Premier League. It’s one of the reasons Van Gaal is so keen to nurse Blind through the remaining games despite a heavy workload already this season.

United have conceded one goal in their last four Premier League games.

Van Gaal has been fortunate that his first choice centre-half, Chris Smalling, has been one of the few players to avoid injury. His appearance against Everton was his 45th of the season, already seven more than his previous best of 38 games in 2013/14. There could still be another 10 to come.

It is Van Gaal’s obsession with organisation that many fans believe is responsible for a lack of incisive, attacking football.

But it has made them solid at the back and allowed players like Smalling to shine. They face their next test against Harry Kane, who scored his 22nd league goal against Liverpool last weekend, at White Hart Lane on Sunday.